1. Technical Field of the Invention
The present invention pertains in general to event notification in a client/server environment, and more particularly, to a method and apparatus for message waiting notification in a client/server environment wherein the client and server communicate via a wireless network.
2. Description of Related Art
Wireless data systems which use a client/server architecture are being developed with the principal data service of these data systems being messaging such as, E-mail, fax-mail and voice-mail, among others. In a client/server environment, when a server receives messages for a client, it would be beneficial if a message waiting notification could be sent to alert the client. Although the server could "call" the client to provide the client message waiting notification, all public standards for client/server architectures do not allow the server to call the client. Instead, the client is required to call the server and establish a "session" before notification and other information can be transferred from the server to the client.
In certain applications, such as a circuit data system used in standard analog cellular telephone systems, no notification mechanism exists. In other applications, solutions to address the problem of message waiting notification have been developed, however, each has a drawback. For example, in a Cellular Digital Packet Data (CDPD) system, mobile clients are assigned a fixed Internet Protocol (IP) address. Mobile clients are required to "log into" the server and maintain a continuous connection. The server can then deliver information to the mobile client at any time since a virtual connection is continuously maintained. IP addresses, however, are limited in number and the use of fixed IP addresses required by the Cellular Digital Packet Data system requires the coordination of all mobile device manufacturers.
It has also been suggested that a Short Message Service (SMS) of a mobile telephone system be used as a message waiting notification vehicle. SMS allows a short message to be delivered to a mobile client. This message can be coded with a standard format such that the client recognizes the SMS message as a message waiting notification. SMS, however, is not a reliable notification system. In many mobile telephone systems, SMS is only provided as a secondary service to voice traffic. Therefore, in heavily loaded mobile telephone systems, SMS messages can be delayed indefinitely making SMS an unreliable notification mechanism. Additionally, SMS messages are typically delivered for a fee and many users may not wish to pay for notification messages.
There is a need therefore, for an efficient, reliable and inexpensive method and apparatus for providing message waiting notification from a server to a client in a wireless client/server architecture.